All 6.2L diesels (any year) are mechanically controlled with no ECM. The 6.2L engine only requires one 12V wire to keep the fuel solenoid open. The glow plug controller can easily be modified to be manually controlled by a rocker switch, if need be.
The later model (1989 and newer, I think) 6.2L diesels may have electronically-controlled automatic transmissions (4L60E or 4L80E), but they will have a stand alone TCM (transmission control module). These can also be replaced with mechanical controls where you shift the transmission manually, if needed.
There were no diesel Suburbans from 1992-1993 when the body style first changed to the GMT400. In 1994, the electronically-controlled 6.5L diesel was used, and you'll want to avoid those for your purposes, unless you swap-in a mechanical injection pump and manual transmission, but that is not all that fun to do.
Yes, the dash pads, and most other parts, are the same for the Suburbans and trucks of the same body style. The 'square body' trucks were built from 1973 - 1988, and the Blazers/Jimmys/Suburbans were built 1973 - 1991.
Casey
1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter